New Level Compiler

The level compiler outputs a kind of a bytecode, which Nethack can read and execute. The output of the executed bytecode program is a dungeon level.

Most of the changes are not visible to normal players, thought it's now not possible to tell which sokoban prize you get from the level layout.
There is also a new wizard-mode extended command #mazewalkmap, which shows the MAZEWALK paths.

Changes under the hood:

-Changing the old-style .des file to this new style requires replacing DOORs with ROOMDOORs if the level type is LEVEL (as opposed to MAZE).

-"IF [xx%] THEN ... ENDIF"
and
"IF [xx%] THEN ... ELSE ... ENDIF"
(see sokoban.des for an example of this)

-It's much easier to shoot yourself in the foot when creating new special levels. For example, MAZE-level shops do not get stocked, unless the shop areas are defined before the doors. (This was evident in orcustown)